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Youngilithus


Classification: ntax_main -> Holococcoliths -> fossil holococcoliths -> Youngilithus
Sister taxa: Daktylethra, Holodiscolithus, Lanternithus, Multipartis, Octolithus, Quadrilateris, Semihololithus, Varolia, Youngilithus, Zygrhablithus ⟩⟨ Aubrysphaera, Corannulus, Orthozygus, Peritrachelina, Unidentified fossil holococcoliths

Daughter taxa (time control age-window is: 0-800Ma)
Youngilithus arcaeformis
Polygonal, medium-sized, non-birefringent holococcolith with a narrow rim spanned by diagonal cross-bars. The rim is coffin-shaped (like a diamond with flattened ends) and usually shows small marginal projections.
Youngilithus bipons
Rhomboid liths with small, marginal projections from the rim and two oblique, parallel, central area bars. Low birefringence image in XPL.
Youngilithus oblongatus
A rectangular, medium-sized, non-birefringent holococcolith with lateral rim projections. The sides of the rectangle are formed from narrow crystallographically distinct units, and some specimens have an internal transverse bar.
Youngilithus pyxis
A rectangular to square, box-like holococcolith constructed from four crystallographically distinct units, with at least two protrusions on each side.
Youngilithus quadraeformis
Square, medium-sized, non-birefringent holoccolith with a narrow rim with small marginal projections, spanned by cross bars parallel with the sides.
Youngilithus transversipons
Elongate rhomboid liths with three oblique, parallel, central area bars. Low birefringence image in XPL.
Youngilithus sp.
Specimens which cannot be assigned to any established species

Taxonomy:
Citation: Youngilithus Bown 2005
Taxonomic rank: genus
Type species: Youngilithus oblongatus Bown, 2005

Synonyms:

Distinguishing features:
Parent taxon (fossil holococcoliths): Holococcolith genera only known from the fossil record
This taxon: Geometrically shaped non-birefringent holococcoliths typically possessing lateral rim spines and central area bars.

Search data:
LITHS: holococcolith, hollow, CROSS-POLARS: V-prominent,
Lith size: 3->8µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of NP16 zone (100% up, 40.4Ma, in Bartonian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP5 zone (59.54-61.51Ma, base in Selandian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Bown, P. R. (2005d). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research. 27(1): 21-95. gs O


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Youngilithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 6-9-2026

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1502 Go to Archive.is to create a permanent copy of this page - citation notes



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